Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare the tool read-only, idempotent, and non-destructive, so the description is not burdened with safety disclosure. It adds useful behavioral context: the data source is Sina, access is keyless, both English and Chinese names are returned, and the exact list of quote fields is enumerated.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact and front-loaded with the core purpose, then support examples, input formats, output fields, routing guidance, and source. It is slightly dense but every sentence contributes useful information; no filler or repetition.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter quote tool with read-only annotations and no output schema, the description is complete: it explains input format, natural-language triggers, return fields, an example, and source. The only schema-provided detail not repeated, the 30-code max, already lives in the input schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents the 'codes' parameter fully. The description reinforces accepted forms ('700, 00700, 0700.HK') and adds examples, but adds little semantic value beyond what the schema already provides.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource: 'Real-time quote(s) for Hong Kong-listed stocks by HKEX code.' It distinguishes itself from hk_resolve_symbol by clarifying that it takes codes, not names, and gives concrete example queries like '00700 quote' and '腾讯股价'.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly says 'If you have a company NAME rather than a code, call hk_resolve_symbol first,' providing a clear when-not-to-use condition and routing to the correct sibling. It also demonstrates usage with a concrete example: hk_quote({ codes: "00700,00005" }).

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.